The following invention relates generally to displaying pages of information on the WorldWide Web ("Web pages"), and specifically to creating interactive Web pages which include multimedia features.
Information is sent to users of the WorldWide Web via Web pages which contain information formatted in hypertext markup language ("HTML"). Users download and view HTML Web pages using a Web browser such as Netscape Corporation's Navigator or Microsoft's Internet Explorer. The pages are displayed one at a time on the user's computer screen. Further information about HTML and the WorldWide Web may be found in The WorldWide Web Handbook by Peter Flynn published by Thomson Computer Press .COPYRGT. 1995, which is herein incorporated by reference. Objects on the pages are laid out two dimensionally, and cannot be overlapped. Each page can contain hypertext links to other pages available on the same web site or on different web sites. The process by which the information contained in Web pages is downloaded by the user's Web browser is called streaming. Often, information such as graphic information which is contained identically on several Web pages is cached by the user so that the information need not be downloaded repeatedly for each page, but instead may be accessed from the user's hard drive.
Caching of Web pages or information contained on Web pages saves considerable time in downloading pages and displaying them, but Web pages are still displayed one at a time. Each Web page can be associated with other Web pages, and it is possible to jump from one page to another Web page via an HTML link. It is not possible, however, for the user to change the information contained in or the appearance of a Web page. Furthermore, information from different web pages cannot be combined by the user in a single web page and rearranged. The user is limited when viewing one Web page to selecting HTML links which will cause the Web page being observed to stop being displayed and cause another Web page to be displayed. When the user selects an HTML link, then a file corresponding to the HTML link is loaded. If the file is an HTML page, then the page which is being displayed is removed from the screen, and the page which was selected by the hypertext link is displayed. The user is limited to browsing among web pages, clicking on links, and loading files. The user's ability to interact with the pages and to combine or associate information from the pages is limited compared to the user's ability to manipulate files and objects on his own computer using a desktop interface. Because the objects displayed on a single web page do not change in response to interaction with the user, the manner in which information can be presented on a Web page is limited.
Javascript provides a way to include programs with the objects which are downloaded in a Web page, enabling the user to change some page properties. More information about Javascript and the Java programming language may be found in Java in a Nutshell by David Flanagan, published by O'Reilly & Associates .COPYRGT.1996. Javascript allows the user to change the file associated with an image tag or to write additional HTML at the end of the document. This capability does not, however give the user the ability to manipulate images on the screen. An image tag in HTML is specified to cover a certain area of the page and is associated with an image file that is displayed in that area. Changing the file associated with the image tag has an effect which is limited to displaying a different image in that same area. The image cannot be moved, resized, overlapped, or combined with other images. Furthermore, a different type of file, such as a text file or a shape file cannot be inserted into the area. Additional HTML objects may be added at the end of the Web page, but those additional objects must be added only at the end of the page and cannot be otherwise arranged or intermingled with previously existing objects on the page.
If a Web page designer desires to otherwise change or modify the information displayed in a Web page based on interaction with the user, the designer is currently limited to stopping the display of the current page and replacing it with another page. HTML allows one bit map background image, which is repeated to fill the entire page. The "foreground" consists of a collection of text and images which are "laid out" next to each other according to the "tags" in the HTML document. The objects may not overlap. Objects may have a link, which may be a uniform resource location ("URL"), which is the name of an "anchor" within the same file to jump to, or the name of another file. Clicking on the link causes the associated file to load. If the file is a sound file, then it plays, and if the file is an HTML page, then the HTML page is loaded and replaces the previous page. This is limiting because in many instances, the Web page designer may desire to have information pop out of the Web page or be highlighted or enlarged on the Web page, while leaving the other information in the Web page on the display. This is, of course, possible by simply replacing the page with other pages which represent modified versions of the page, but this method of modifying a page is cumbersome and ineffective to animate the page.
These limitations on the display of Web pages are especially noticeable to the multimedia user. It is possible, for instance, to play a sound in response to the pressing of a button or selection of text by the user of a Web page, but the appearance of the page cannot be altered in connection with the playing of the sound without removing the page from the display and displaying a new page. Furthermore, when a video clip or animation is desired to be played from a Web page, the Web page must include a two dimensional space which is made available for a second application to play the movie or animation. The animation cannot pop up on the page and temporarily overlap other objects or spaces on the page. It would be desirable if the space for the video clip or animation could simply appear on the page when needed and disappear when finished. It would also be desirable if a movie or animation could be displayed in the space directly by the Web browser without needing to access a separate application for playing the movie or animation.
What is needed is a way to modify and animate the information displayed on a single Web page without removing that page from the display and substituting another Web page. Freed from the constraint of the need to design and display separate pages for each change which is to be displayed, a designer could animate Web pages and make them interact with the user.